HCoP-B: A Hierarchical Care-of Prefix With BUT Scheme for Nested Mobile Networks

With current Internet Engineering Task Force (IETF) network mobility (NEMO) basic support (NBS) to manage mobility of a mobile network that moves as a whole, all communication to and from mobile network nodes (MNNs) inside the mobile network must go through multiple tunnels between upstream mobile routers and their home agents. This results in the nonoptimized route and increased packet delay between communication peers. Hence, numerous NEMO schemes such as reverse routing header (RRH), mobile IPv6 route optimization for NEMO (MIRON), and care-of prefix (CoP) have been proposed to solve it. Whenever the whole mobile network or its mobile subnet changes its points of network attachments, a large number of duplicate binding update messages are sent from the handoff mobile network to all connecting correspondent nodes on the Internet to establish a direct and optimized packet route between them, which raises the corresponding consumed Internet and local wireless network bandwidth and, in turn, increases the packet transmission delay. However, traditional NEMO schemes cannot solve this serious binding update storm problem. In this paper, we apply the hierarchical concept to the CoP scheme as the Hierarchical CoP (HCoP) scheme and then enhance the HCoP with a novel binding update tree (BUT) structure as the HCoP-B for efficient NEMO management of the nested mobile network. Compared with the traditional RRH, MIRON, and HCoP with intensive performance analyses and simulations, HCoP-B achieves the shortest handoff latency, the lowest number of duplicate binding update messages conveyed over the Internet, and the least amount of consumed Internet and local wireless network bandwidth for session initialization and route optimization of all connecting correspondent nodes at the expense of a small amount of extra binding caches in the BUT. We also discuss important issues about HCoP-B deployment, security, and mobility anchor point (MAP) location alternatives. Consequently, HCoP-B achieves the correspondent node (CN)'s route optimization and resolves the associated binding update storm problem simultaneously for the nested mobile network.